Several c41 questions..
So, how important is is really to blix at 95-105F? I've been blixing anywhere from 65-80 (whatever the room temperature is) with literally no (observable?) impact on the negatives (granted I haven't taken out my densitometer, but they scan fine...)
Second, I intentionally skipped stabilizer on a few rolls and I am seeing zero impact on the output months later (I scanned the roll fresh out and again months later with no appreciable differences)...Is stabilizer really necessary for modern color emulsions? Is it really preserving the dye couplers from turning brown in modern films?
Third, with respect to dilution of c41 developer: Is there a sense or understanding of how much c41 developer can be diluted to produce a "quality" image? I've been experimenting with color stand development for the last few years and have had very good (and reproducible if semi-stand) results from 1:4 - 1:9 dilutions to 650ml. One shot, of course.
Fourth- I read somewhere (and subsequently tried) to fix c41 in bw fixer and although the image "fixed", the "bypass" effect I was interested in was essentially an opaque negative. Is bleach bypass literally just bypassing the bleach process? I can't see how there would be any latent image without getting rid of all those sulfides...I eventually blixed the roll at room temp and it cleared nicely in a few minutes..
Finally, does anyone know if color film reticulates like bw film when the apply exceedingly high temperatures to it?
Thanks in advance for your answers and also for not trolling me by asking me "why the hell would you do that?" :)
I have not stabilsed many C41 rolls for some time as I ran out ! HOWEVER -- on one roll of 120 XP2 Super I did a year ago I notice some uneven 'brown' effects compared with the usual more 'Magenta' colour
Regarding RETICULATION -- YES -- Ilford XP2 Super and their FUJI equivalent DOES reticulate easily on the backing super-coat if a 'PRE-SOAK' is used and also if you RINSE quickly with water at 100oF between the Developer and the Bleach, so it is really necessary to go straight into the Bleach from the Developer. I have NOT had any Reticulation of COLOUR C41 emulsions under those condtions of pre-soak and rinse.
I think there is quite a large of temps for blix without ill effects as you have demonstrated. Not using a stabiliser might give problems many months down the line. That is months which equate to several years because I understand stabiliser to prevent "bugs" attacking the emulsion.
Thanks to both of you for the replies..
My process is as follows:
3. Pre-soak ~39C for 1-3m depending on my impatience
2. Develop at ~39C for 3.5m
3. Rinse 4-5x tap water, 25-30C
3. Blix 6.5m (give or take) at room temperature (varying between 20C-25C during the Summer)
4. Wash 10m, tap water, 25-30C
5. Pflo 1m
Would anyone like to chime in on the stabilizer and bleach bypass questions?
Best regards and Thanks!
As others have said the stabilizer is a necessary step to stop fungal/bacterial attacks on the film. This may only occur after many years, but could ruin your negatives in the long run. Stabilizer is also said to stabilize the dyes in the film, although this is no longer necessary as C41 the film has had stabilizer built in for the last decade or so. There is an interesting post here about it http://www.apug.org/forums/forum40/1...tabilzers.html. Stabilizer is not necessary for B&W as the silver has natural anti-bacterial/fungal properties.
Bleach bypass is not a technique i've played with myself, but my understanding is that it is often just reduced time spent in the bleach rather than totally skipping the step altogether. As you say this would end up with very dense negatives.
As far as the temp of the blix stage goes, I imagine there is plenty of scope in the temperature you use, but if you are heating up the developer, why not do the blix at the same time. Blix times extend considerably as you reuse it and having it at higher temperatures may help to keep the times within reason.
Good point on the Blix. I suppose I could. It is a lot easier for me to worry about only heating up one of the two. Obviously the developer temperature is more important than the blix so that's what I chose to heat up. I don't mind heating up the blix at the same time, I'm thinking I will just stop keeping tabs on the exact temperature (which is usually my procedure)..I've also noticed when I do a quick one-off roll or two using bw tanks that the temperature of the chemistry causes, I think, the plastic to slightly swell which in turn causes leaking when agitating....This doesn't happen when the chemistry is at room temperature..
Finally, is there an idea on just how much bleach one is supposed to use for the bypass process? Ratio, or?
First of all develop at 38 degree C for 3 min 15 sec, not 39 degree C for 3 min 30 sec.
Originally Posted by fotoobscura
Skip the rinse in step 3. It is not a good practice to rinse between development and bleach.
Separate blix into bleach and fix. It is not good to blix C-41 films.
Instead of Pflo in step 5 use a stabilizer or Kodak C-41 Final Rinse. This is a critical step. Final Rinse is very cheap. Don't skip it or change it.
Using a water bath makes it very easy to keep processinging solutions at the right temperature. If you vary from the recommended processing either with temperature, agitation, dilution, etc you are not going to get optimal results.
That sounds like perhaps instructions for a rotary and different chemistry. I'm not using a rotary. I usually buy Tetenal press kits which prescribe in fact 39C for 3.5M.
Could you please humor me and explain to me why it's not good practice to rinse between developer and bleach? (especially if the rinse temperature is near developer and blix temperatures)? Both developer and blix can be reused repeatedly. It occurs to me rinsing after the developer ensures less/little developer is introduced into the blix when it is stored. I have been doing it this way for many years with no ill effects. But I'm always looking to learn a thing or two! (or ten!)
Relatively recent example using my above mentioned process:
In theory some residue of developer will benefit the bleach bath as it creates the right pH. In practice if you want to reuse bleach without polluting it the better solution is an "acid stop" bath which serves both purposes, make an acid environment and avoid polluting bleach with developer. That's what I read here on APUG. Your mileage may vary.
Originally Posted by fotoobscura
"Acid stop" can either mean acetic acid or citric acid.
From my notes:
Acetic acid: economical, effective, not risky for the film, dangerous for persons, polluting, stinking, reusable, well preserved; can be used more times when diluted at 2%. For one-shot better using 1% or 1.5% dilution.
Citric acid: more expensive, not dangerous, odourless, must be used on the same day of dilution, and some people report the possibility of problems (my notes not very specific).
I chose acetic acid. I still have to perform my first C-41 bath, my "chemistry" is still sealed. Hope I'll do it in the next few weeks.